A patient is undergoing a physical and reveals a history of chicken pox. The doctor states he doesn't need a vaccine for chicken pox anymore since he has already been exposed to the disease. What type of immunity does this describe?

A. Passive artificial: Passive artificial immunity occurs when antibodies are given through injections, such as immune globulin. Immunity develops immediately but is temporary and does not involve the person’s own immune response. B. Active natural: Active natural immunity develops after exposure to a pathogen through natural infection, such as having chicken pox. The body produces its own antibodies and memory cells, providing long-term protection. C. Active artificial: Active artificial immunity is acquired through vaccination, where antigens are introduced to stimulate antibody production without causing the disease. This is not applicable since the patient had the actual infection. D. Passive natural: Passive natural immunity occurs when antibodies are transferred naturally, such as from mother to fetus through the placenta or through breast milk. This does not apply to immunity gained from having chicken pox.